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Abstract:

An etching composition and a method of manufacturing a display substrate
using the etching composition are disclosed. The etching composition
includes phosphoric acid (H3PO4) of about 40% by weight to
about 70% by weight, nitric acid (HNO3) of about 5% by weight to
about 15% by weight, acetic acid (CH3COOH) of about 5% by weight to
about 20% by weight, and a remainder of water. Thus, a metal layer
including copper may be stably etched.

Claims:

1. An etching composition comprising: phosphoric acid (H3PO4)
of about 40% by weight to about 70% by weight; nitric acid (HNO3) of
about 5% by weight to about 15% by weight; acetic acid (CH3COOH) of
about 5% by weight to about 20% by weight; and a remainder of water.

2. The etching composition of claim 1, wherein an amount of phosphoric
acid is between about 40% by weight and about 45% by weight, an amount of
nitric acid is between about 10% by weight and about 13% by weight, an
amount of acetic acid is between about 12% by weight and about 15% by
weight, and an amount of water is between about 27% by weight and about
48% by weight.

3. A method of manufacturing a display substrate, the method comprising:
forming a first metal layer including copper on a base substrate; forming
a photo pattern on the first metal layer; patterning the first metal
layer using the photo pattern as an etching stop layer and an etching
composition including phosphoric acid of about 40% by weight to about 70%
by weight, nitric acid of about 5% by weight to about 15% by weight,
acetic acid of about 5% by weight to about 20% by weight and a remainder
of water, to form a first metal pattern including a first signal line and
a first electrode connected to the first signal line; forming a second
metal pattern including a second signal line crossing the first signal
line and a second electrode connected to the second signal line; and
forming a pixel electrode connected to a thin-film transistor including
the first and second electrodes and connected to the first and second
signal lines.

4. The method of claim 3, wherein the first metal pattern is formed by:
forming a second metal layer including titanium under the first metal
layer, before forming the first metal layer; and etching the second metal
layer using a second etching composition including hydrofluoric acid
after patterning the first metal layer.

5. The method of claim 3, wherein the first metal pattern is formed by:
forming a second metal layer including a metal selected from the group
consisting of copper alloy, molybdenum and molybdenum alloy under the
first metal layer, and etching the second metal layer using the etching
composition.

6. The method of claim 3, wherein forming the second metal pattern
comprises: forming a third metal layer including copper on the base
substrate on which the first metal pattern is formed; and patterning the
third metal layer using the etching composition.

7. The method of claim 6, wherein forming the second metal pattern
comprises: forming a fourth metal layer including titanium under the
third metal layer before forming the third metal layer; and etching the
fourth metal layer using the second etching composition including a
hydrofluoric acid after patterning the third metal layer.

8. The method of claim 6, wherein forming the second metal pattern
comprises: forming a fourth metal layer including a metal selected from
the group consisting of copper alloy, molybdenum and molybdenum alloy,
etching the fourth metal layer using the etching composition.

9. The method of claim 3, further comprising: forming a semiconductive
layer on the base substrate on which the first metal pattern is formed;
and patterning the semiconductive layer using the etching composition to
form an active pattern between the first electrode and the second
electrode.

10. The method of claim 9, wherein the semiconductive layer comprises at
least one of amorphous silicon and metal oxide.

12. The method of claim 3, further comprising: forming a semiconductive
layer under the first metal layer; and wherein etching the first metal
layer comprises etching the semiconductive layer and the first metal
layer using the etching composition to form the first signal line, the
first electrode and an active pattern between the first and second
electrodes.

13. The method of claim 12, wherein the semiconductive layer comprises at
least one of amorphous silicon and metal oxide.

14. The method of claim 3, further comprising: forming a copper layer on
the base substrate before forming the first metal layer; patterning the
copper layer using the etching composition to form a preliminary pattern
including a preliminary signal line and a preliminary electrode connected
to the preliminary signal line; and removing the preliminary pattern
using the etching composition, wherein the first metal pattern is formed
on the base substrate from which the preliminary pattern is removed.

Description:

[0001] PRIORITY STATEMENT

[0002] This application claims priority under 35 U.S.C. §119 to
Korean Patent Application No. 10-2011-0115783, filed on Nov. 8, 2011 in
the Korean Intellectual Property Office (KIPO), the contents of which are
herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0003] 1. Field of the Invention

[0004] Example embodiments relate to an etching composition and a method
of manufacturing a display substrate using the etching composition. More
particularly, example embodiments relate to an etching composition used
for etching a copper layer and a method of manufacturing a display
substrate using the etching composition.

[0005] 2. Description of the Related Art

[0006] Generally, a display substrate used in a display apparatus includes
a thin-film transistor ("TFT") as a switching element for driving a
pixel, signal lines connected to the TFT, and a pixel electrode. The
signal lines include a gate line transmitting a gate driving signal and a
data line transmitting a data driving signal.

[0007] As the size of display apparatuses increases and also customer's
requirements that display apparatuses have high resolution, the length of
the gate and data lines is increased while at the same time the width of
the gate and lines is decreased, and as a result electric resistance is
increased. Thus, a resistance-capacitance ("RC") signal delay is caused.
In order to solve this RC signal delay problem, gate and data lines are
formed from a metal having a relatively low resistance. Copper is a metal
having a relatively low resistance and when used for forming gate and
data lines has excellent electric conductivity and has a resistance much
lower than aluminum or chrome. Furthermore, copper is relatively abundant
as a natural resource. However, the resistance of copper against an
oxidizer is higher than that of aluminum or chrome, so that a strong
oxidizer is required for etching a copper layer when forming signal
lines.

[0008] Copper etchants that include a strong oxidizer are effective for
etching the copper layer, however, patterns previously formed in prior
processes may be easily damaged from such a copper etchant. A
conventional peroxide-based etchant is sometimes replaced with an etchant
including a persulfuric acid-based compound as a main etching element to
reduce etching of patterns previously formed in prior processes when
etching the copper layer. However, such an etchant is unstable when
stored at a room temperature, and has a limitation to maximize a number
of substrates treated by the etchant.

SUMMARY OF THE INVENTION

[0009] An etching composition for a copper layer having high storage
stability at a room temperature and capable of increasing a number of
treating substrates is provided.

[0010] A method of manufacturing a display substrate using the etching
composition is also provided.

[0011] According to one aspect, an etching composition includes phosphoric
acid (H3PO4) of about 40% by weight to about 70% by weight,
nitric acid (HNO3) of about 5% by weight to about 15% by weight,
acetic acid (CH3COOH) of about 5% by weight to about 20% by weight,
and a remainder of water.

[0012] In another aspect, an amount of phosphoric acid may be between
about 40% by weight and about 45% by weight, an amount of nitric acid may
be between about 10% by weight and about 13% by weight, an amount of
acetic acid may be between about 12% by weight and about 15% by weight,
and an amount of water may be between about 27% by weight and about 48%
by weight.

[0013] A method of manufacturing a display substrate is provided. In the
method, a first metal layer including copper is formed on a base
substrate, and a photo pattern is formed on the first metal layer. The
first metal layer is patterned using the photo pattern as an etching stop
layer and an etching composition to form a first metal pattern including
a first signal line and a first electrode connected to the first signal
line. The etching composition includes phosphoric acid of about 40% by
weight to about 70% by weight, nitric acid of about 5% by weight to about
15% by weight, acetic acid of about 5% by weight to about 20% by weight
and a remainder of water. A second metal pattern including a second
signal line crossing the first signal line and a second electrode
connected to the second signal line is formed. A pixel electrode
connected to a thin-film transistor including the first and second
electrodes is formed. The thin-film transistor is connected to the first
and second signal lines.

[0014] A second metal layer including titanium may be formed under the
first metal layer before forming the first metal layer, and the second
metal layer may be etched using a second etching composition different
from the etching composition of the first metal layer. The second etching
composition may include hydrofluoric acid. Thus, the first metal pattern
including the first and second metal layers may be formed.

[0015] A second metal layer including copper alloy, molybdenum or
molybdenum alloy may be formed under the first metal layer before forming
the first metal layer, and the second metal layer may be etched using the
etching composition of the first metal layer. Thus, the first metal
pattern including the first and second metal layers may be formed.

[0016] The second metal pattern may be formed via substantially the same
process as the first metal pattern.

[0017] A semiconductive layer may be formed on the base substrate on which
the first metal pattern is formed, and the semiconductive layer may be
patterned using the etching composition of the first metal layer, and
thus an active pattern is formed between the first and second electrodes.
The semiconductive layer may include amorphous silicon or metal oxide.

[0018] A semiconductive layer may be formed under the first metal layer.
When the first metal layer is etched, the semiconductive layer and the
first metal layer may be etched using the etching composition to form the
first signal line, the first electrode and an active pattern disposed
between the first and second electrodes.

[0019] A copper layer may be formed on the base substrate before forming
the first metal layer, and the copper layer may be patterned using the
etching composition of the first metal layer to form a preliminary
pattern including a preliminary signal line and a preliminary electrode
connected to the preliminary signal line. The preliminary pattern is
removed using the etching composition. Here, the first metal pattern may
be formed on the base substrate which the preliminary pattern is removed.

[0020] The etching composition including phosphoric acid, nitric acid and
acetic acid may be stably kept at a room temperature, and a number of
treating substrates may be increased. That is, ability to etch the
substrates may be improved. Therefore, although a thickness of a copper
layer is increased, the number of the treating substrates may be
maximized to improve the productivity.

[0021] In addition, the etching composition may etch a copper alloy layer,
a molybdenum layer or a molybdenum alloy layer with the copper layer, so
that a multi-layered metal layer may be etched whole. Further, the
etching composition may etch a semiconductive layer including amorphous
silicon or metal oxide with the copper layer so that process patterning
the copper layer and the active layer may be simplified.

[0022] Furthermore, when a metal pattern formed by patterning the copper
layer is faulty, the metal pattern is removed and a new metal pattern is
formed again to reprocess the substrate using the etching composition,
which does not include a fluorine-based compound. The etching composition
used in removing the metal pattern may minimize patterns which are
already formed before removing the metal pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other features and advantages will become more
apparent by describing example embodiments thereof with reference to the
accompanying drawings, in which:

[0024] FIGS. 1 to 4 are cross-sectional views illustrating a method of
manufacturing a display substrate according to an example embodiment;

[0025] FIGS. 5 to 8 are cross-sectional views illustrating a method of
manufacturing a display substrate according to another example
embodiment; and

[0026] FIGS. 9 to 11 are cross-sectional views illustrating a method of
manufacturing a display substrate according to still another example
embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an etching composition and a method of manufacturing a
display substrate including a pattern formed using the etching
composition will be illustrated with reference to the accompanying
drawings.

[0028] Etching Composition

[0029] An etching composition according to an exemplary embodiment
includes phosphoric acid (H3PO4) of about 40% by weight to
about 70% by weight, nitric acid (HNO3) of about 5% by weight to
about 15% by weight, acetic acid (CH3COOH) of about 5% by weight to
about 20% by weight, and a remainder of water. With respect to the amount
of water, the "remainder water" means that, given a total weight of the
etching composition of "100%," an amount of water is equal to 100% minus
the total percent by weight of phosphoric acid, nitric acid and acetic
acid. Hereinafter, each of components of the etching composition will be
described.

[0030] Phosphoric Acid

[0031] Phosphoric acid is a compound substantially oxidizing copper of a
copper layer.

[0032] When an amount of phosphoric acid is less than about 40% by weight
based on the total weight of the etching composition, an etching rate of
the copper layer is notably reduced or the copper layer is not uniformly
etched. In addition, when the amount of phosphoric acid is greater than
about 70% by weight, the etching composition etches excessively, so that
it is difficult to control the quantity of the copper layer that is
etched. When the copper layer is excessively etched, the width of the
signal line formed using the copper layer is less than the width that the
signal line is designed to be, such design having taken into
consideration the resistance property of copper in setting the width of
the signal line.

[0033] Therefore, the etching composition includes phosphoric acid between
about 40% by weight and about 70% by weight based on the total weight of
the etching composition. More usually, the amount of phosphoric acid may
be between about 40% by weight and about 45% by weight based on the total
weight of the etching composition.

[0034] Nitric Acid

[0035] Nitric acid is a compound that oxidizes copper of the copper layer
and supports phosphoric acid. In addition, nitric acid may control the
acidity (pH) of the etching composition that includes phosphoric acid as
a main oxidizer.

[0036] When an amount of nitric acid is less than about 5% by weight based
on the total weight of the etching composition, the etching rate of the
copper layer is decreased, and the copper layer is etched non-uniformly.
When the copper layer is non-uniformly etched, a stain may be shown. In
contrast, when the amount of nitric acid is greater than about 15% by
weight, nitric acid in combination with the phosphoric acid excessively
etches the copper layer.

[0037] Therefore, the etching composition includes nitric acid between
about 5% by weight and about 15% by weight based on the total weight of
the etching composition. More usually, the amount of nitric acid may be
between about 10% by weight and about 13% by weight based on the total
weight of the etching composition.

[0038] Acetic Acid

[0039] Acetic acid controls the acidity of the etching composition with
nitric acid, and uniformly etches the copper layer to improve the
linearity of the signal line.

[0040] When an amount of acetic acid is less than about 5% by weight based
on the total weight of the etching composition, the etching rate of the
copper layer is decreased and the etching composition has difficulty
etching the copper layer. Thus, the copper layer may remain after the
etching process. When the amount of acetic acid is greater than about 20%
by weight, the copper layer is excessively etched and the etching rate of
the etching composition is not controlled.

[0041] Therefore, the etching composition includes acetic acid between
about 5% by weight and about 20% by weight based on the total weight of
the etching composition. More usually, the amount of acetic acid may be
between about 12% by weight and about 15% by weight based on the total
weight of the etching composition.

[0042] Water

[0043] Water includes deionized water. For example, water may have a
degree of purity of water that is used for manufacturing a
semiconductive, and have, for instance, a specific resistance of equal to
or greater than about 18 Me/cm. Water is added to the phosphoric acid,
nitric acid and acetic acid so that the total weight of the etching
composition is about 100% by weight. An amount of water in the etching
composition may, for example, be between about 27% by weight and about
48% by weight.

[0044] Preparation of an Etching Composition

[0045] An etching composition according to Example 1 including about 42%
by weight of phosphoric acid, about 10.5% by weight of nitric acid, about
13.5% by weight of acetic acid and about 34% by weight of water was
prepared. The etching composition of Example 1 does not include any one
of (or collectively) a peroxide-based etchant, a persulfuric acid-based
compound, or a fluorine-based compound, which are compound more
conventionally used to etch copper layer.

[0046] In addition, etching compositions according to Comparative Examples
1 to 6 as listed in the following Table 1 were prepared.

[0047] Experiment 1 for Evaluating an Etching Property of the Etching
Compositions

[0048] For evaluating the etchant compositions of Example 1 and
Comparative Examples 1-6, substrate Samples 1 to 7 were prepared in which
a titanium layer and a copper layer were sequentially formed on a glass
substrate having a size of about 550 mm×650 mm. The titanium layer
had a thickness of about 200 Å and the copper layer had a thickness
of about 3,000 Å. A photo pattern was formed on the copper layer.

[0049] An ETCHER (product name, AStech, Korea), which is an experimental
spray type etching device, was set up at a temperature of about
40° C., and then the copper layer of each of the Samples 1 to 7
was etched for about 60 seconds using the etching compositions according
to Example 1 and according to Comparative Examples 1 to 6. After the
copper layer of substrate Samples 1 to 7 was etched, the titanium layer
in each of substrate Samples 1 to 7 was etched using a hydrofluoric acid
solution that included hydrofluoric acid and water having a dilution
ratio of about 1:300.

[0050] Substrate Samples 1 to 7 were washed by deionized water, and were
dried using a drying device. Then, the photo pattern in substrate Samples
1 to 7 was removed. A taper angle and a critical dimension skew ("CD
skew") of the metal pattern that included the copper layer and the
titanium layer were measured in each of substrate Samples 1 to 7 using an
S-4700 (product name) scanning electron microscope of Hitachi
Cooperation. In addition, an etching rate for each of substrate Samples 1
to 7 was measured.

[0051] Results 1 of the Evaluation of an Etching Property of the Etching
Composition

[0052] In the metal pattern formed using the etching composition according
to Example 1, the copper layer pattern had a taper angle in a range
between about 30° and 50°, and a CD skew in a range between
about 0.56 μm and about 0.76 μm. Here, an etching rate of the
etching composition according to Example 1 was between about 4.5
μm/minute and about 5.5 μm/minute.

[0053] In contrast, when the copper layer of each of the substrate Samples
2 to 7 was etched by the etching compositions according to Comparative
Examples 1 to 6, the etching compositions according to Comparative
Examples 1, 3 and 5 did not etch the copper layer. On the other hand, the
etching compositions according to Comparative Examples 2, 4 and 6
entirely removed the copper layer, although the photo pattern protected
the copper layer in Samples 3, 5 and 7.

[0054] Discussion of Experiment 1 and Results 1

[0055] According to the above Experiment 1 and Results 1, when phosphoric
acid of less than about 40% by weight is included in the etching
composition such as Comparative Example 1, etching the copper layer is
difficult. In addition, when an amount of nitric acid or acetic acid is
less than about 5% by weight in the etching compositions, such as in
Comparative Examples 3 and 5, etching the copper layer is difficult, even
though the amount of phosphoric acid is adequate.

[0056] In addition, when phosphoric acid of greater than about 70% by
weight is included in the etching composition such as Comparative Example
2, the etching rate is excessively great and is difficult to control,
even though the amounts of nitric acid or acetic acid are adequate. When
nitric acid of greater than about 15% by weight or acetic acid of greater
than about 20% by weight is included in the etching compositions of
Comparative Examples 4 and 6, the etching rate is excessively large and
is difficult to control even thought the amount of phosphoric acid is
adequate.

[0057] Therefore, the etching composition for the copper layer includes
phosphoric acid of about 40% by weight to about 70% by weight, nitric
acid of about 5% by weight to about 15% by weight, acetic acid of about
5% by weight to about 20% by weight, and a remainder of water. Because
the etching composition does not etch the titanium layer, an additional
etching composition including hydrofluoric acid is required for etching
the titanium layer. Thus, a step for etching the titanium layer is added
in a process of etching a multi-layered structure that includes a
titanium layer and a copper layer. Nevertheless, because the thickness of
the copper layer as a main signal line is greater than that of the
titanium layer, the exposure time of the copper layer to a compound that
includes fluorine is decreased when two different etching composition are
used as compared to when hydrofluoric acid is added in the etching
composition used for etching the copper layer. Thus, damage to the
substrate can be minimized

[0058] Experiment 2 for Evaluating an Etching Property of an Etching
Composition

[0059] Substrate Sample 8 was prepared in which a metal layer and a copper
layer were sequentially formed on a glass substrate having a size of
about 550 mm×650 mm. A photo pattern was formed on the copper
layer. The metal layer included a copper alloy layer which was magnesium
aluminum copper alloy (CuMgAl alloy) and thus that included about 2 atom
% of magnesium and about 8 atom % of aluminum. The thickness of the metal
layer was about 200 Å, and the thickness of the copper layer was
about 3,000 Å.

[0060] Substrate Sample 9 was prepared in which a metal layer and a copper
layer were sequentially formed on a glass substrate having a size of
about 550 mm×650 mm. A photo pattern was formed on the copper
layer. The metal layer included a CuMgAl alloy and had a thickness of
about 100 Å, and the copper layer had a thickness of about 5,000
Å.

[0061] Substrate Sample 10 was prepared in which a metal layer and a
copper layer were sequentially formed on a glass substrate having a size
of about 550 mm×650 mm. A photo pattern was formed on the copper
layer. The metal layer included a CuMgAl alloy and had a thickness of
about 200 Å, and the copper layer had a thickness of about 5,000
Å.

[0062] Substrate Sample 11 was prepared in which a metal layer was formed
on a glass substrate having a size of about 550 mm×650 mm. A photo
pattern was formed on the metal layer. The metal layer included a CuMgAl
alloy and had a thickness of about 5,000 Å.

[0063] An ETCHER (product name, AStech, Korea), which is an experimental
spray type etching device, was set up at a temperature of about
40° C., then the copper layers of each of substrate Samples 8 to
11 were etched for about 60 seconds using the etching compositions
according to Example 1. Substrate Samples 8 to 11 were washed with
deionized water, and were dried using a drying device. Then, the photo
patterns in substrate Samples 8 to 11 were removed, and a taper angle and
a critical dimension skew ("CD skew") of the metal patterns including the
copper layers and the titanium layers were measured in each of substrate
Samples 8 to 11 using an S-4700 (product name) scanning electron
microscope of Hitachi Cooperation. In addition, an etching rate for each
of substrate Samples 8 to 11 was measured.

[0064] Results 2 of the Evaluation of the Etching Property of the Etching
Composition

[0065] In metal patterns formed using the etching composition according to
Example 1, each of the metal patterns formed on substrate Samples 8, 9
and 10 had a taper angle, respectively, in a range between about
23° and 33°, in a range between about 20° and about
30°, and in a range between about 26° and about 36°.
In addition, the metal pattern formed using substrate Sample 11 and the
etching composition according to Example 1 had a taper angle in a range
between about 10° and about 20°.

[0066] In the metal patterns formed using the etching composition
according to Example 1, each of the metal patterns formed on substrate
Samples 8, 9 and 10 had a taper angle, respectively, in a range between
about 0.38 μm and about 0.58 μm, in a range between about 0.27
μm and about 0.47 μm, and in a range between about 0.26 μm and
about 0.36 μm. In addition, the metal pattern formed using substrate
Sample 11 and the etching composition according to Example 1 had a CD
skew in a range between about 0.38 μm and about 0.44 μm.

[0067] Here, an etching rate of the etching composition according to
Example 1 was, respectively, between about 7.7 μm/minute and about 7.9
μm/minute for substrate Samples 8, 9 and 10, and was between about 3.4
μm/minute and about 3.5 μm/minute for substrate Sample 11.

[0068] Discussion of Experiment 2 and Results 2

[0069] According to the above Experiment 2 and Results 2, the copper alloy
layer is integrally etched, that is, etched in the same etching
procedure, with the copper layer using the etching composition according
to present embodiments. In addition, the etching property for the copper
alloy layer using the etching composition is favorable.

[0070] Experiment 3 for an Etching Property Evaluation of an Etching
Composition

[0071] Substrate Sample 12 was prepared in which a molybdenum layer having
a thickness of about 200 Å and a copper layer having a thickness of
about 3,000 Å were sequentially formed on a glass substrate having a
size of about 550 mm×650 mm. A photo pattern formed on the copper
layer were prepared.

[0072] Substrate Sample 13 was prepared in which an indium gallium zinc
oxide layer having a thickness of about 1,000 Å, a molybdenum layer
having a thickness of about 200 Å and a copper layer having a
thickness of about 3,000 Å were sequentially formed on a glass
substrate having a size of about 550 mm×650 mm. A photo pattern was
formed on the copper layer.

[0073] Substrate Sample 14 was prepared in which a molybdenum tungsten
layer having a thickness of about 300 Å and a copper layer having a
thickness of about 3,000 Å were sequentially formed on a glass
substrate having a size of about 550 mm×650 mm. A photo pattern was
formed on the copper layer.

[0074] An ETCHER (product name, AStech, Korea), which is an experimental
spray type etching device, was set up at a temperature of about
40° C., then the copper layer of each of substrate Samples 12 to
14 was etched for about 60 seconds using the etching compositions
according to Example 1. Substrate Samples 12 to 14 were washed by
deionized water, and were dried using a drying device. Then, the photo
pattern in substrate Samples 8 to 11 was removed, and a taper angle and a
critical dimension skew ("CD skew") of the metal patterns that included
the copper layer and the titanium layer were measured in each of
substrate Samples 12 to 14 using S-4700 (product name) scanning electron
microscope of Hitachi Cooperation.

[0075] Results 3 of the Etching Property Evaluation of the Etching
Composition

[0076] In metal patterns formed using the etching composition according to
Example 1, each of the metal patterns formed on substrate Samples 12 and
13 had a taper angle in a range between about 71° and 81°.
In addition, the metal pattern formed using substrate Sample 14 and the
etching composition according to Example 1 had a taper angle in a range
between about 80° and about 90°.

[0077] In the metal patterns formed using the etching composition
according to Example 1, each of the metal patterns formed on substrate
Samples 12, 13 and 14 had a taper angle, respectively, in a range between
about 2.85 μm and about 3.01 μm, in a range between about 2.69
μm and about 2.89 μm, and in a range between about 4.5 μm and
about 5.0 μm.

[0078] Discussion of Experiment 3 and Results 3

[0079] According to the above Experiment 3 and Results 3, the molybdenum
layer, the indium gallium zinc layer as a metal oxide and the molybdenum
tungsten layer are integrally etched with the copper layer using the
etching composition according to present embodiments. In addition, an
etching property of the copper alloy layer using the etching composition
is favorable.

[0080] Method of Manufacturing a Display Substrate

[0081] Hereinafter, a method of manufacturing a display substrate using
the etching composition will be illustrated in detail with reference to
the accompanying drawings.

[0082] FIGS. 1 to 4 are cross-sectional views illustrating a method of
manufacturing a display substrate according to an example embodiment.

[0083] Referring to FIG. 1, a first metal layer 122 and a second metal
layer 124 are sequentially formed on a base substrate 110, and a first
photo pattern 210 is formed on the second metal layer 124.

[0084] The first metal layer 122 includes, for example, titanium, and the
second metal layer 124 includes, for example, copper. Each of the first
and second metal layers 122 and 124 may be entirely formed on the base
substrate 110 by a sputtering process.

[0085] Referring to FIG. 2, the second metal layer 124 is etched using the
first photo pattern 210 as an etching stop layer.

[0086] The second metal layer 124 is etched using an etching composition
including phosphoric acid (H3PO4) of about 40% by weight to
about 70% by weight, nitric acid (HNO3) of about 5% by weight to
about 15% by weight, acetic acid (CH3COOH) of about 5% by weight to
about 20% by weight, and a remainder of water. The etching composition of
the second metal layer 124 is substantially the same as the etching
composition described above. Thus, any repetitive description will be
omitted. The etching composition does not include a hydrofluoric acid, so
that the etching composition oxidizes the second metal layer 124, but
does not oxidize the first metal layer 122.

[0087] Therefore, when the etching composition is provided to the base
substrate 110, the etching composition may selectively etch the second
metal 124 left exposed by the first photo pattern 210.

[0088] Referring to FIG. 3, the first metal layer 122 is etched using the
patterned second metal layer 124 and the photo pattern 210 as an etching
stop layer. The first metal layer 122 may be etched by an etching
composition including hydrofluoric acid. For example, the etching
composition of the first metal layer 122 may be a solution of
hydrofluoric acid diluted with water to a dilution ratio between about
1:100 and about 1:400.

[0089] The first photo pattern 210 is removed to form a first metal
pattern MP1 (FIG. 4) including the first metal layer 122 and the second
metal layer 124. The first metal pattern MP1 includes a first signal line
GL and a gate electrode GE as a first electrode of a thin-film transistor
("TFT") connected to the first signal line GL. The first signal line GL
may be a gate line connected to the gate electrode GE and transmitting a
gate driving signal.

[0090] According to the description illustrated in FIGS. 1 to 3, the
second metal layer 124 is etched using the etching composition including
phosphoric acid, nitric acid and acetic acid, and the first metal layer
122 is etched using the etching composition including hydrofluoric acid,
and thus a taper angle and a critical dimension skew ("CD skew") may be
easily controlled, as compared to forming the first metal pattern MP1
using an integrated etching composition for a copper layer and a titanium
layer which etches both layers with the same etching composition. In
addition, the amount of time that the base substrate 100 is exposed to
the etching composition that includes hydrofluoric acid is much smaller
than of the amount of time that the base substrate 100 is exposed to the
etching composition that includes phosphoric acid, nitric acid and acetic
acid. That is, when the first metal layer 122, is etched, the second
metal layer 124 is also exposed to hydrofluoric acid. The first metal
layer 122, however, has a thickness that is about 1/10 the thickness of
the second metal layer 124, so the amount of time needed to etch the
first metal layer 122 is less than that of the first metal layer 124,
which reduces that amount of time that the second metal layer is exposed
to the hydrofluoric acid. Thus, the etching composition of the present
embodiments is used for etching the second metal layer 124, and the first
metal layer 122 is etched by a different etching composition, for
instance that includes hydrofluoric acid, so that the damage of the base
substrate 110 and layers thereon may be minimized.

[0091] Referring to FIG. 4, a first insulating layer 130 is formed on the
base substrate 110 on which the first metal pattern MP1 is formed, and an
active pattern AP is formed on the first insulating layer 130 in a region
corresponding to the gate electrode GE.

[0092] The active pattern AP may include a semiconductive layer 142 and an
ohmic contact layer 144. The ohmic contact layer 144 may be omitted. The
semiconductive layer 142 may include, for example, amorphous silicon
("a-Si") or metal oxide. The metal oxide may serve as an oxide
semiconductive, for example, the metal oxide may include indium gallium
zinc oxide.

[0093] Then, a second metal pattern MP2 is formed on the base substrate
110 on which the active pattern is formed. The second metal pattern MP2
includes a second signal line DL crossing the first signal line GL, a
source electrode SE as a second electrode of the TFT connected to the
second signal line DL, and a drain electrode DE. The second signal line
DL may be a data line transmitting a data driving signal.

[0094] The second metal pattern MP2 is formed by pattering a third metal
layer 152 formed on the base substrate 110 on which the active pattern AP
is formed and a fourth metal layer 154 formed on the third metal layer
152. A second photo pattern (not shown) is formed on the fourth metal
layer 154, and the third and fourth metal layers 152 and 154 are etched
using the second photo pattern as an etching stop layer.

[0095] For example, the third metal layer 152 includes titanium, and the
fourth metal layer 154 includes copper. Here, the third metal layer 152
is etched using an etching composition including hydrofluoric acid, and
the fourth metal layer 154 is etched using the etching composition
according to the present embodiments. A process for etching the third and
fourth metal layers 152 and 154 is substantially the same as illustrated
in FIGS. 2 and 3, and thus any repetitive description will be omitted.

[0096] Alternatively, the third metal layer 152 may include, for example,
copper alloy, molybdenum or molybdenum alloy, etc. In such a case, the
third metal layer 152 may be etched using the etching composition that is
used for etching the fourth metal layer 154. Thus, the substrate 110 and
layers formed thereon do not need to be exposed to an etchant, for
example, hydrofluoric acid, that may be damaging to the layers formed on
the substrate when the third metal layer 152 is etched.

[0097] A second insulating layer 160 is formed on the base substrate 110
on which the second metal pattern MP2 is formed, and the second
insulating layer 160 on the drain electrode DE is removed to form a
contact hole CNT partially exposing the drain electrode DE.

[0098] Then, a pixel electrode PE is formed on the base substrate 110 on
which the contact hole CNT is formed. The pixel electrode PE makes
contact with the drain electrode DE through the contact hole, and thus
the pixel electrode PE is connected to the TFT.

[0099] According to the above description, although two etching steps are
required in order to form the first metal pattern MP1, the second metal
layer 124 is etched using different etching composition from the etching
composition of the first metal layer 122 so as to improve the reliability
of the etching of the second metal layer 124. In addition, the fourth
metal layer 154 is etched using the etching composition of the first
metal layer 122 so that the damages of the first metal pattern MP1 may be
prevented in forming the second metal pattern MP2.

[0100] FIGS. 5 to 8 are cross-sectional views illustrating a method of
manufacturing a display substrate according to another example
embodiment.

[0101] Referring to FIG. 5, a first metal layer 122 and a second metal
layer 124 are sequentially formed on a base substrate 110, and a first
photo pattern 210 is formed on the second metal layer 124. Here, the
first metal layer 122 includes, for example, copper alloy, molybdenum or
molybdenum alloy, and the second metal layer 124 includes copper. The
first and second metal layers 122 and 124 may be formed by a sputtering
process.

[0102] Referring to FIG. 6, the first and second metal layers 122 and 124
are patterned using the first photo pattern 210 as an etching stop layer
to form a first metal pattern MP1. The first metal pattern MP1 includes
(FIG. 7) a first signal line GL and a gate electrode GE. The first signal
line GL serves as a gate line transmitting a gate driving signal and
connected to the gate electrode GE.

[0103] The first and second metal layers 122 and 124 are etched using an
etching composition including phosphoric acid (H3PO4) of about
40% by weight to about 70% by weight, nitric acid (HNO3) of about 5%
by weight to about 15% by weight, acetic acid (CH3COOH) of about 5%
by weight to about 20% by weight, and a remainder of water. The etching
composition is substantially the same as the etching composition
described above, and thus any repetitive description will be omitted. The
first and second metal layers 122 and 124 are etched, and the first photo
pattern 210 is removed.

[0104] Referring to FIG. 7, a first insulating layer 130, an
semiconductive layer 142, an ohmic contact layer 144, a third metal layer
152 and a fourth metal layer 154 are sequentially formed on the base
substrate 110 on which the first metal pattern MP1 is formed. A second
photo pattern 220 is formed on the fourth metal layer 154.

[0105] The ohmic contact layer 144 may be omitted. The semiconductive
layer 142 may include, for example, amorphous silicon or metal oxide. For
example, the metal oxide may include gallium indium zinc oxide. The third
metal layer 152 may include, for example, copper alloy, molybdenum or
molybdenum alloy. The fourth metal layer 154 may include copper.

[0106] The ohmic contact layer 144, the semiconductive layer 142, the
third and fourth metal layers 152 and 154 are etched using the etching
composition and the second photo pattern 220 as an etching stop layer.
The etching composition of the embodiments may etch amorphous silicon or
metal oxide together with a metal layer including copper or molybdenum.
That, the etching composition may be an integrated etching composition
that etches the ohmic contact layer 144, the semiconductive layer 142,
and the third and fourth metal layers 152 and 154 in the same etch
procedure.

[0107] For example, the second photo pattern 220 may include a first
thickness portion 222 having a first thickness and a second thickness
portion 224 having a second thickness thinner than the first thickness.

[0108] Referring to FIG. 8, the ohmic contact layer 144, the
semiconductive layer 142, the third and fourth metal layers 152 and 154
are etched to form a second metal pattern MP2 and an active pattern AP.

[0109] When the second metal pattern MP2 is viewed in a plan view, the
second metal pattern MP2 includes the third and fourth metal layers 152
and 154. As components, the second metal pattern MP2 includes a second
signal line DL, a source electrode SE and a drain electrode DE, and the
active pattern AP includes the ohmic contact layer 142 and the
semiconductive layer 144.

[0110] After the ohmic contact layer 144, the semiconductive layer 142,
and the third and fourth metal layers 152 and 154 are firstly etched
using the etching composition of the present embodiments and the second
photo pattern 220 as an etching stop layer, the second thickness portion
224 of the second photo pattern 220 is removed to form a residual
pattern. The third and fourth metal layers 152 and 154 with the ohmic
contact layer 144 are secondly etched using the residual pattern as an
etching stop layer to form the active pattern AP and the second metal
pattern MP2.

[0111] Then, a second insulating layer 160 is formed on the base substrate
110 on which the second metal pattern MP2 is formed, and a contact hole
CNT is formed in the second insulating layer 160. A pixel electrode PE is
formed on the base substrate 110 on which the contact hole CNT is formed
so that the pixel electrode PE makes contact with the drain electrode DE.
The pixel electrode PE is connected to a thin-film transistor including
the gate electrode GE, the active pattern AP, the source and drain
electrodes SE and DE.

[0112] Alternatively, and different from the description in FIGS. 5 and 6,
the first metal layer 122 of the first metal pattern MP1 in FIG. 8 may
include titanium instead of a copper ally. When the first metal layer 122
includes titanium, the first metal pattern MP1 may be formed by the
process illustrated in FIGS. 1 to 3.

[0113] According to the above description, the etching composition
including phosphoric acid, nitric acid and acetic acid integrally etches
the ohmic contact layer 144, the semiconductive layer 142, and the third
and fourth metal layers 154 and 154 to simplify the process of forming
the second metal pattern MP2 and the active pattern AP. In addition,
reliability of the etching process of the ohmic contact layer 144, the
semiconductive layer 142, the third and fourth metal layers 152 and 154
may be improved.

[0114] In addition, in forming the first metal pattern MP1 or the second
metal pattern MP2, if the first metal pattern MP1 or the second metal
pattern MP2 is determined to be faulty, the etching composition can be
used to remove the first or second metal pattern MP1 or MP2 to recycle
the base substrate 110. For example, before forming the first metal
pattern MP1, a single copper layer or a multi-layered metal layer
including a copper layer is patterned to form a preliminary pattern
substantially the same as the first metal pattern MP1, and if the
preliminary pattern is determined to be faulty, the preliminary pattern
is removed using the etching composition. Then, the first metal pattern
MP1 may be formed via the processes illustrated in FIGS. 5 and 6. In
forming the preliminary pattern, the preliminary pattern is a pattern
trying to be formed by a user. However, in forming the first metal
pattern MP1, the preliminary pattern is already the removed pattern
before forming the first metal layer 122 to be a pattern previously
formed by the user. The etching composition is used for a reprocess to
recycle the base substrate 110 and to decrease a manufacturing cost.

[0115] FIGS. 9 to 11 are cross-sectional views illustrating a method of
manufacturing a display substrate according to still another example
embodiment.

[0116] Referring to FIG. 9, a semiconductive layer 51, an ohmic contact
layer S2, a first metal layer 123 and a second metal layer 125 are formed
on a base substrate 110, and a first photo pattern 310 is formed on the
second metal layer 125.

[0117] The shape of the first photo pattern 310 is substantially the same
as the shape of the second photo pattern 220 illustrated in FIG. 7. The
semiconductive layer 51 may include, for example, amorphous silicon or
metal oxide. The first metal layer 123 may include, for example, copper
alloy, molybdenum or molybdenum alloy, and the second metal layer 125 may
include copper.

[0118] The ohmic contact layer S2, the semiconductive layer 51, and the
first and second metal layers 123 and 125 are patterned using the first
photo pattern 310 as an etching stop layer and an etching composition
including phosphoric acid (H3PO4) of about 40% by weight to
about 70% by weight, nitric acid (HNO3) of about 5% by weight to
about 15% by weight, acetic acid (CH3COOH) of about 5% by weight to
about 20% by weight, and a remainder of water. The etching composition
may integrally etch the ohmic contact layer S2, the semiconductive layer
S1, the first and second metal layers 123 and 125 in the same etching
procedure.

[0119] Alternatively, when the first metal layer 123 includes titanium,
the first metal layer 123 is etched using an etching composition of
dilute hydrofluoric acid after the second metal layer 125 has been etched
using the etching composition including phosphoric acid, nitric acid,
acetic acid and water of the present embodiments. Then, the ohmic contact
layer S2 and the semiconductive layer S1 may be etched using the etching
composition of the second metal layer 125 or a different etching
composition from the etching composition of the second metal layer 125.

[0120] Referring to FIG. 10, the ohmic contact layer S2, the
semiconductive layer S1, and the first and second metal layers 123 and
125 are patterned to form a first metal pattern MP1 and an active pattern
AP.

[0121] The first metal pattern MP1 includes a first signal line DL, a
source electrode SE connected to the first signal line DL, and a drain
electrode DE spaced apart from the source electrode SE. The first signal
line DL may be a data line transmitting a data driving signal. The active
pattern AP includes the ohmic contact layer S2 and the semiconductive
layer S1.

[0122] A first insulating layer 130, a third metal layer 153 and a fourth
metal layer 155 are sequentially formed on the base substrate 110 on
which the first metal pattern MP1 and the active pattern AP are formed.
The third metal layer 153 may include a copper alloy, molybdenum or
molybdenum alloy, and the fourth metal layer 155 may include copper.

[0123] Referring to FIG. 11, the third and fourth metal layers 153 and 155
are patterned to form a second metal pattern MP2. The second metal
pattern MP2 includes a second signal line GL crossing the first signal
line DL, and a gate electrode GE connected to the second signal line GL.
Here, the second signal line GL may be a gate line transmitting a gate
driving signal. The third and fourth metal layers 153 and 155 may be
etched using the etching composition used for etching the first and
second metal layers 123 and 125.

[0124] Alternatively, when the third metal layer 153 includes titanium and
the fourth metal layer 155 includes copper, the third metal layer 153 is
etched using an etching composition that includes hydrofluoric acid after
the fourth metal layer 155 has been etched using the etching composition
including phosphoric acid, nitric acid and acetic acid of the present
embodiments, to form the second metal pattern MP2.

[0125] A second insulating layer 160 is formed on the base substrate 110
on which the second metal pattern MP2, and the first and second
insulating layers 130 and 160 on the drain electrode DE are patterned to
form a contact hole CNT. A pixel electrode PE is formed on the base
substrate 110 on which the contact hole CNT is formed.

[0126] According to the embodiments, the etching composition including
phosphoric acid, nitric acid and acetic acid may be stably kept at a room
temperature, and a number of treating substrates may be increased. That
is, an etching ability capable of treating the substrates may be
improved. Therefore, although a thickness of a copper layer is increased,
the number of substrates that may be etched may be maximized to improve
the productivity.

[0127] In addition, the etching composition may etch a copper alloy layer,
a molybdenum layer or a molybdenum alloy layer with the copper layer, so
that a multi-layered metal layer may be etched whole. Further, the
etching composition may etch a semiconductive layer including amorphous
silicon or metal oxide with the copper layer, so that process patterning
the copper layer and the active layer may be simplified.

[0128] Furthermore, when a metal pattern formed by patterning the copper
layer is faulty, the metal pattern is removed and a new metal pattern is
formed again to reprocess the substrate using the etching composition,
which does not include fluorine-based compound. The etching composition
according to the present invention in removing the metal pattern may
minimize patterns which are already formed before removing the metal
pattern.

[0129] The foregoing is illustrative and is not to be construed as
limiting thereof. Although a few example embodiments have been described,
those skilled in the art will readily appreciate that many modifications
are possible in the example embodiments without materially departing from
the novel teachings and advantages of the present invention. Accordingly,
all such modifications are intended to be included within the scope of
the present invention. In the claims, means-plus-function clauses are
intended to cover the structures described herein as performing the
recited function and not only structural equivalents but also equivalent
structures. Therefore, it is to be understood that the foregoing is
illustrative and is not to be construed as limited to the specific
example embodiments disclosed, and that modifications to the disclosed
example embodiments, as well as other example embodiments, are intended
to be included within the scope of the disclosure, including the appended
claims.